Bus and switch station



April 8, 1930. A. M. ROSSMAN BUS AND SWITCH STATION Filed Nov. 20, 1925 5 Sheets-Sheet l MN m Q April 8, 1930. A. M. RossMAN' BUS AND SWITCH STATION Filed Nov. 20, 1925 5 Sheets-Sheet 2 fizz/W QZ/erz 121705577202 1 ILul:

April 8, 19m A. M. ROSSMAN v BUS AND SWITCH STATION Filed Nov. 20, 1 1925 5 Sheets-Sheet 5 520212202." Qlkrz ffjlajjma/z MMM j w A. M. ROSSMAN BUS AND SWITCH STATION April 8, 1930.

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A. M. ROSSMAN BUS AND SWITCH STATION Filed Nov. 20, 1925 5 SheetsSheet 5 jz 'z vezzffi @2272 fffosjmarz Q, (h v individual to the lines.

Patented Apr. 8, 1930 UNITED STATES PATENT OFFICE ALLEN M. ROSSMAN, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO ROSSMAN PATENTS, INCORPORATED, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS BUS AND SWITCH STATION Application filed November My invention relates to bus and switch stations for modern high tension alternating current power generating and distributing systems.

The development of the electric power industry has followed general manufacturing practice. The production of electric current is nothing more than a special manufacturing process and naturally it has followed the practice of mass production, i. e., production of a standardized unit in great quantity for the sake of economy.

However, certain special conditions, namely, load factor and demand for continuity of service, are peculiar to the manufacture and distribution of electric current which have resulted in the interconnection of generating stations. v

These two tendencies, namely, mass production, i. e., generation of electric power in great quantity, and interconnection, have introduced a new hazard, or, rather, an old hazard in greatly exaggerated form, i. e., danger of interphase short circuit on the busses. The danger is two-fold, first, the liability to property damage and the loss to life, which such a short circuit can cause, and second, the liability to interruption of service on a wide scale.

The only practicable way, under present circumstances, to distribute the electric power of the generating system, is to deliver the power onto a bus or busses and from these take off the connections to the various lines through switching and protective apparatus Interconnection with other generating stations is made by lines connecting the busses of the two stations.

For reasons well known to those skilled in the art, the busses and switching apparatus for the various connections are grouped and connected together into a permanent unit known as a bus and switch station, or, more briefly, as a switch station. This may consist of an open air arrangement known as a switch yard, or when the apparatus and conductors are housed, it is known as a switch house. i

The constant increase in the size of stations 20, 1925. Serial No. 70,319.

and the increase in interconnected capacity has finally reached a point where the possible damage that can be done to life and property by a bus short circuit, has reached such enormous proportions that the art has been forced to depart from known practice to give a greater degree of inherent safety.

The problem has been discussed above purely on the basis of changing conditions due to increase in capacity, i. e., generated kilowatts, but with increased capacity of stations increased voltage to cover a greater consuming area has been required. This increase of voltage comes upon the busses and has immensely complicated the problem, since a peculiar train of complications follows increases in voltage.

The problem may be viewed on the basis of insurance. With the increased investment and with refinements in the art which have cut the cost of delivering a unit of electricity to the consumer, the risk of loss per dollar has not only failed to diminish, but has actually increased. This increased risk can be charged directly against the danger of a bus short in the switch station.

I have attacked the above problem with a View to providing a station which will secure inherent safety of a high order and at a cost which will be moderate in proportion to the advantages secured.

I have conceived the possibility of providing complete individual insulation of a very high order for all main conductors of a power switch station. I am aware of the prior art stations of the J amieson type and of the Reyrolle type, and am familiar with their disadvantages.

The J amieson system involves phase segregation or isolation as an essential feature to provide safety. This is extravagant of space and provides no weather protection in an out door station or yard.

The Reyrolle system involves heavy castings, which are very expensive, common to all phases and employs a solid filling of insulation poorly adapted for high tension. For high tension the expense of this system becomes prohibitive. It furthermore does not safety.

I have conceived the possibility of employing a self-healing insulation individual to each phase conductor such, for example, as insulating oil. Such a station is wholly new in the art. To make the same practicable, T have devised a system of unit construction and assembly which is also new in the art and which cuts down the cost of the station to a figure far below that of a station of anywhere near the comparable degree of safety, constructed under any system of the prior art. This decrease in cost is secured in two ways, first, by-

the relatively simple and inexpensive means which I employ to construct the station, and, second, by compactness.

The element of compactness affects the cost, first, in a saving of space required, and, second, in a saving of material required. The only space now required by my system between conductors or apparatus of different phase, is that required to insure reasonable freedom from transmission of physical force or the causing of physical injury to one phase from or by injury to conductors or apparatus of a difierent phase. Aside from that requirement, conductors or apparatus of opposite or different phase may now be grouped as closely as desired. Such close grouping as is possible with reasonable safety from physical transmission of damage, permits a shortening of conductors, insulation sheathing and framing to a point where the resulting structure presents a saving in cost and increase of safety which mark this invention as an outstanding achievement in the art.

The specific means by which T secure the aforesaid results will be described hereafter in detail, but consists generally in the employment of a loose tubular enclosure or sheathing for the separate conductors, which sheathing is filled with a fluid dielectric, preferably insulating oil. The sheathing is preferably sectionalized by suitable barriers to localize the efi'ects of leakage or loss of'oil. The conductors are completely housed and insulated by this construction throughout their entire length in the station. The conductors are preferably provided with a wrapped or other solid insulation adequate for normal protection in case of loss of oil.

The construction of the conductors and of the sheathing is coordinated to provide a new form of insulated conductor having highly desirable and novel characteristics both in point of ease of erection, low cost and superior operating ability.

The conductors are essentially of large current carrying capacity for carrying high tension alternating current. They are cut to convenient short lengths and provided with wrapped factory made insulation except at the ends where they are left bare and provided with connecting lugs or ends suitable for clamping to adjacent ends or to the terminals of apparatus, or other interconnection. The joints of the conductors to each other and to terminals of apparatus and the like, such as transformers, switches, reactors, instrument transformers, and the like, are housed by junction boxes having removable sides or portions for providing access to make the joints or to gain access to the joints. The con ductor between joints is enclosed by rela tively short lengths of tubing, the ends of which are secured to adjacent junction boxes to form a mechanically continuous sheath for receiving the oil filling. Tn the course of con struction this sheathing, which comprises the junction boxes and tube lengths, is first assembled in place on a suitable supporting structure and then the conductors are inserted therein and joined in the junction boxes. Then the junction boxes are closed and the sheathing filled with insulating oil.

The tube lengths between junction boxes are relatively short and within the lengths employed are substantially rigid. The tubes preferably are nowhere bent and, hence, runs of conductor are either straight or led off at an angle at a junction box, where any predetermined angle may be made. Preferably, but not necessarily, T employ only 90 angles and, hence, ll can employ throughout standard rectangular junction boxes. The tubes are supported entirely by the junction boxes and they can be, and preferably are, thin metallic tubes affording a very considerable strength. The tubes and junction boxes are made of metal, substantially nonmagnetic, or of low magnetic permeability, to cut down electrical losses due to flow of alternating current in the contained individual phase conductor.

The tubes and junction boxes'are joined by companion flanges which are suitably se cured together, as, for example, by bolting. Obviously, within my invention other means of oining the tubes and junction boxes might be employed.

The filling of oil is maintained in each section by suitable reserve maintained in an expansion tank and connected to the desired sections.

The junction boxes may be varied for difierent situations, but for taking off taps are made two units high, each unit being the space required to connect a tube and provide suitable clearance with an adjacent tube. Hence, in taking off taps or connections to line conductors from the bus conductors, these tap connections may be made by a short vertical connection in the junction box and a transverse run of sheathed conductor at a level above or below the level of the bus or other connected conductor. This reduces the different parts required to be carried in stock to very small number.

The material for erecting a station may be carried in stock to a very large extent. The consequent ease and low expense of erectlon is apparent.

Now in order to acquaint those skilled 1n the art with the manner of constructing and operating a device embodying my inventlon, I shall describe in conjunction with the accompanyingdrawings a specific embodlment of my invention, consisting of a part of a typical three-phase bus and switch station.

In the drawings:

Fig. 1 is a plan of a part of an electricalbus and switching station embodyingmy armor-insulation from transformer to transmission line;

Fig. 2 is a top plan of the same;

Fig. 3 is a perspective of a typical example of part of my armor-lnsulatlng housing;

Fig. 4 is an enlarged vertical section of a typical housing junction box for encloslng a connection between bus conductor sectlons running at right angles to each other;

Fig. 5 is an enlarged perspectlve of such a junction box unit of the housing;

Fig. 6 is a horizontal section of such a housing; O 0

Fig. 7 is a vertical section of a unctlon box for an ammeter connection including a current transformer;

Fig. 8 is an end elevation of a bus bar insulator for spacing the bus bar from the housing;

Fig. 9 is a side elevation of such an insulator;

Fig. 10 is a horizontal section through a junction box enclosing a bus bar expansion joint;

Fig. 11 is a vertical section through an armor pipe expansion unit;

Fig. 12 is a section through a sealing connection between junction boxes, and

Fig. 13 is a. section through a housing enclosing an oil circuit breaker contact.

In order to demonstrate the applicability of my armor-insulation I have illustrated a typical power house installation of threephase high tension heavy duty conductors, connection and appliances from a transformer A which is one of a suitable bank of transformers, through oil circuit breakers B individual to a line and reactors C to line disconnect switches D where connection is made to a typical high tension power transmission line. My system of armor-insulation is concerned primarily with the protective armoring of the heavy duty conductors and connections whereby the high tension load current is conveyed from the high voltage source, such as transformers, to the high voltage transmission lines, which are sometimes in the form of cables and sometimes in the form of open wires, and whereby current, usually at greatly reduced voltages and amperage, is tapped oil from the main conductors for application to indicating and recording instruments, controlling apparatus and the like. Therefore,

detailed description and illustration of the' ed is part of a three-phase system, for the sake of brevity and clearness all of the component parts are not shown in triplicate but, where it is believed that the arrangement will be obvious from a disclosure of only one phase, two phases are largely or entirely omitted. Also I have shown only a single line as leading off from the bus, but it will be apparent that as many lines as desired may be employed, and since they are of the same construction as the one illustrated, I have not deemed it necessary to show more than one.

A bus bar section for each phase leads through an individual terminal or sealing junction box 5 to a similar angle junction box 6. In junction box 6 the bus bar is, by a suitable connection, turned from a vertical to a substantially horizontal section, which is enclosed in a pipe 7. Pipe 7 may include an expansion joint 8 to be hereinafter described.

Often it is necessary or desirable to locate the oil circuit breakers and other apparatus on a level below the transformers. In such event each bus bar is led through pipe 7 into a junctionbox 9 where by a suitable connection between two sections, its direction is changed from the horizontal to a vertical plane. If desired a current tap 10, associated with the busbar through a current transformer located in junction box 9, may lead to an ammeter for indicating the amount of current flowing. From junction box 9 the bus bar, enclosed in pipe 11, is led to a double junction box consisting of the directly connected boxes 12 and 13. Between these two boxes 12 and 13 is a sealing connection to be hereinafter described. The junction boxes and pipes heretofore mentioned are connected together, as will presently appear, to provide a separate chambar for each phase and, because of the seals or separations these chambers are separated from the transformer at the higher level and from the chambers containing the bus bar and associated connections in the lower level of the network. The reasons such separation is sometimes desirable will be presently explained.

In the bottom junction box 13 the bus bar of each phase is, by means of a suitable connection between two bus bar sections, changed from the vertical plane to a substantially horizontal plane at the desired lower level. A tap taken from the bus bar inside of lower box 13 may lead into a similar box 1% which encloses a suitable potential transformer. The low voltage secondary of this potential transformer may be connected by leads 15 to a switchboard voltmeter or other device. From the bottom box 13 a horizontal run or section of each bus bar is led through a pipe 16 to a junction box 17 where, by means of a suitable conductor, it is extended by a section which runs in a pipe 18 to connect with the proper terminals of oil circuit breaker B. When a bus bar run or section i long enough for its expansion and contraction under temperature variations to interfere with the maintenance of proper connections and when it is desired to eliminate undue strains created thereby a bus bar expansion joint such as hereinafter 1 described may be inserted and housed in a junction box 19.

From the opposite terminals of each phase of oil circuit breaker B a line bus conductor section is led through a pipe 20 to an angle junction box 21. Within junction box 21 each bus bar is, by a suitable connection, joined to a section extending at a right angle and, passing out through the side of the junction box, is carried through a pipe 22 to the vicinity of the reactors C. I

The reactors are current limiting devices well understood by those skilled in the art. Their function is to limit the maximum flow of current which can be drawn from the bus by a short circuit on the line. Hence, beyond the point where the line bus conductor emerges from the reactor, the danger of a short circuit on the Vitals of the system is gone,and the line conductors may be cabled or led bare to'overhead conductors and no special precautions are necessary to guard against destruction of the station by a short circuit beyond the reactors.

Since the performance of an entire transmission system may be dependent upon proper circuit breaker operation, and because oil circuit breakers are subject to injury due to the severe duty which they must perform, it is frequently considered good practice to provide duplicate sets of oil circuit breakers so that there always may be a set in reserve. When such a layout is deemed necessary or advisable one set of transformers may feed through duplicate sets of armored conductors and connections and oil circuit breakers, the conductors from the circuit breakers bein joined together in junction boxes 23 located between the duplicate oil circuit breakers and the reactors.

In front of the reactors each bus bar section in pipes 22 enters an angle junction box 24 where, by means of a suitable connector, it is turned at a right angle and, through pipe 25, is carried to the corresponding reactor G. If desired a current transformer and a potential transformer may be associated with each bus bar before it enters the reactor, such transformers being located in junction boxes 26 and 27 respectively. From these unction boxes leads may be carried to appropriate indicating and recording instruments or to remote control switches at other devices operable or reduced current and voltage.

After passing through the reactors the current reaches the line disconnect switches D where connection is made to the high tension transmission cable or wires.

In the embodiment chosen for illustration the bus bar and connection housing formed by the joined pipes and junction boxes of each phase provides a single independent chamber 8" from the seal in junction box 13 to one side of the oil circuit breaker. Another chamber is formed by the joined pipes and junction boxes associated with the bus bar sections and connections of each phase from the other side of the oil circuit breaker to the reactors. Still another chamber is'formed by the pipes and junction boxes on the line side of the disconnect switches. Thus the joined pipes and junction boxes form a separate armo-ring housing providing a multi sectioned chamber for receiving the bus bar sections and associated connections of each phase.

A high degree of protection can be pro-- vided by forming the joined pipes and junc- 9::

tion boxes of a strong relatively non-magnetic or low magnetic permeability metal such as manganese steel. Ordinarily it is the better practice to carefully insulate the bus bars by appropriate solid insulation, such as paper tape or other suitable means, and properly support them out of contact with their enclosing pipes. As an added protection and in order to seal the conductors and connections and their coverings of solid insulation against moisture, the housing chambers may be partly or wholly filled with a high dielectric fluid such for example as a freely flowing petroleum oil. Oil having a body about like that of automobile engine oil will give good re- 11o sults under ordinary conditions. By providing fluid tight joints between pipes and junction boxes the bus bars and associated connections can be kept in a bath of oil and by dividing the housing chamber into a numberJ the heat they would generate in the outer armor might produce such high temperatures that injury to ordinary solid and liquid dielectrics or insulations would result. However, by curtailing the magnitude of these magnetic effects as for example, by constructing the outer armor of low magnetic permeability metal,that is, metal which is relatively non-magnetic as compared to ordinary iron or steel, the magnetic effects in the armor can be kept low enough to prevent injurious temperature rises. In fact, the temperature of the sheath or armor may be kept so low relative to the conductors carrying the load current that it will serve as a heat radiator to assist in the dissipation of heat from the conductors, and metals having magnetic permeability as low as manganese steel will prevent the formation of excessive magnetic effects even under conditions of rather abnormally high load current values. Yet, often it may not be necessary to use metals having as low a magnetic permeability as manganese steel. Consequently, in instances where the load currents are relatively small, metals of higher magnetic permeability than manganese steel and which may be less expensive and more easily worked may be employed. Therefore, for each particular installation the pipes and junction boxes may be constructed in whole Or in part of metals which will offer the necessary mechanical strength and protection and which will not, whensubjected to the influences of the load current of the system, permit magnetic effects of suflicient volume to raise the temperature of the sheath or armor above the point where the solid insulation and dielectric will be injured.

The separate and independent housing of each phase, each housing being grounded, prevents communication between phases without first passing through two separated thicknesses of the armor metal in addition to whatever insulation may be applied directly to the conductors and connections and such fluid dielectric as the chambers may contain. Furthermore any gases which may be generated and liberated as a result of a fault developed on one phase can not reach the other two phases. Consequently a short circuit between phases is practically impossible.

In order to afford a reserve of the oil dielectric and to accommodate the expansion and contraction thereof under temperature variations, oil supply and expansion tanks are provided, preferably located slightly above the housing chamber or chambers to which they are connected. Thus an oil supply and expansion tank 30 may serve the chambers from the transformers A to the seals in junction boxes 12-43 of all three phases. This tank, which may be formed in precisely the same way as, a junction box, is directly connected to the middle phase bus bar junction box 6 by a fluid tight joint. Small pipes 31 connect tank 30 to junction boxes 6 of the and in direct communication with junction box 17 of the middle phase and connected to the junction boxes 17 of the other two phases by small supply pipes 33. Similarly an oil reserve expansion tank 34, above and in direct communication with the middle phase junction box 21 and connected by pipes 35 to the corresponding junction boxes of the other tWo phases, will serve the housing chambers of all three phases from theoil circuit breakers to the reactors. Each oil reserve expansion tank is'v'ented to atmosphere in any appropriate manner, such as the small U-shaped vent pipe 36. Of course, a larger or smaller subdivision of the housing chambers into separate oil reservoirs may be used if desired and the arrangement of oil reserve expansion tanks may be varied greatly to suit particular conditions.

Having thus outlined the general character and application of my armor-insulating system I will now describe some of the details whereby such a complete system may be assembled at the point of installation from a relatively small variety of units or standard parts.

0 Fig. 3 shows, in enlarged perspective, a typical collection of junction boxes and pipes such as may be used in duplication and in various combinations and arrangements to accommodate either simple or very complicated bus bar networks. The portion of the switch station heretofore outlined which has been chosen to thus illustrate a typical assemblage and arrangement of parts, extends from the sealing junction boxes 12-13 through the junction box 17 of one phase.

The pipe which forms the enclosing porlions of the housing for bus bar 39 may be built up of one or several standard lengths or units securely and tightly joined end to end. Each section or unit of pipe is provided with an end flange 40 adapted to fit against and cooperate with a corresponding flange on the abutting end of the next pipe section or j unction box as occasion may require. These flanges may be tightly and rigidly fastened together by suitable means such as bolts 4 and sealing gaskets 42 of appropriate material. such as fiber, may be interposed between them to insure a fluid tight joint. The flanges may be attached on the ends of the pipes in various ways, such as by welding or soldering the ends of the pipes within them. By making these pipe units of manganese steel a relatively light, rigid, strong and low magnetic permeability bus bar housing of any desired length may be fabricated.

It is to be observed that the oil containing sheathing in each case is individual to the conductor, i. e., contains throughout only one phase of the bus or line. The sheathing consists of the junction boxes and tubes as shown in a typical example in Fig. 3. The tubing is employed only in straight relatively short lengths and within the lengths employed it is rigid. Bending of the sheathing is not contemplated, as all changesin direction are made inthe junction boxes, and such changes the box.

'ofdirection are preferably 90 changes, al-

though it can beseen that the junction boxes may be formed to embody any angular relation desired. These junction boxes support the tubes at their ends and-,due to their short length, no other support is required. Due to the rigidity of the short lengths of relatively large diameter tubing the resulting structure is rigid. The weight of the con ductors is carried in the tubes and junction boxes without distorting the tubing and without requiring the tubes to be supported between junction boxes.

The junction boxes, which in general and in most installations may be practically identical, may be built up of angle corner pieces 43 and cover or side plates attached thereto by suitable means such as bolts 44, as shown most clearly in Figs. 5, 6 and 7. Each corner piece may be formed from a strip of angle manganese steel having a cross section of almost a closed rectangle. These corner pieces are welded, riveted or otherwise secured together to form a skeleton framework to which the six sides may be applied to close The almost closed rectangular cross section of the supporting angle pieces to a large extent houses the heads of the side plate attaching bolts tt. Packing gaskets may be interposed between the framework and the side plates to insure fluid tight joints.

The side plates for the junction boxes may be in the majority of cases of two types, one with an opening and pipe connecting flange and the other without an opening and flange. They may be stamped from sheets of manganese steel or other suitable low magnetic permeability material, the flanges being formed integrally therewith or formed separately and secured tothe plates by welding or in some other approved manner. The flanged side plates 45 are used to form those faces of a junction box which receive a pipe or are directly connected to another box'while the unflanged solid side plates 46 are used on those faces through which no connections are to be made. By locating the flange and opening at the proper distance on one side of the center of side plate 45 the one general type of plate may be used where the connection to pipes or other boxes come on either side of the center line oit' the box. Merely reversing the plate end for end will reverse the relative position of the connecting flange.

When the length of any run of bus bar is so great that its cumulative expansion and contraction may become troublesome expansion joints may be interposed to relieve the difficulty. Such a bus bar expansion joint is located in junction box 19 and shown in detail section in Fig-10. The adjacent ends of bus bar sections 39 provide a series of slots for receiving the opposite ends of conducting fiexible leaves 47 and these leaves and the bus bar ends are secured together by bolts, rivets, solder or other well known methods. Thus there is provided a relatively flexible joint between the two sections of solid bus bar where compensation is made for contraction and expansion. This expansion joint is housed in a junction box 19 substantially like those heretofore described. It has the skeleton framework of angle pieces 43 to which are bolted tour solid side plates 48. The ends of the framework are closed by two flanged end plates 49 to which the flanged ends of pipe sections 16 are bolted Suitable gaskets may be used to seal all of the joints so that the fluid dielectric may not leak therethrough.

The typical assembly of junction boxes and bus bar pipes just described :torrns a rigid fluid tight housing for enclosing the bus bar sections, connections and an expansion joint if one is needed. These housings, one for each phase, can be assembled at the power house or other point of installation by merely collecting, arranging and joining together such pipe sections and junction boxes as the bus bar and connection lay-out will require. The sides of the box frameworks, which will be ultimately closed by solid side plates, may be left open until the bus bars are laid and all of their connections completed. Then the boxes are completely closed and, if the liquid dielectric is to be used, the chamber of the housing may be filled with oil.

The bus bar sections, which may be composed of copper or other suitable material in the form" of solid orlaminated bars, tubing or cable and of round, rectangular or other desired cross section may be furnished by the factory in suitable lengths and ordinarily covered by approved solid insulation such as the tape previously mentioned. After the housing is completely-installed except for some of the junction box side plams, the bus bar sections, all of which usually may be straight, can be inserted through the boxes and pulled or pushed through the pipes. In order to insure that the bus bar will not contact with the inside wall of a pipe, and to assist in the insertion of the sections through the pipe, insulating spacers may be applied 51 in space provided therefor between flanges.

These spools may be composed of porcelain, wood, fiber or other suitable insulating material and should have an external diameter somewhat less than the internal diameter of the pipe. Thus they do not interfere with the drawing or forcing of the associated bus bar section through the pipe or with the free flow of oil to fill the housing. In fact their presence may be of material assistance in laying the 'bus bar sections in their respective pipes. They may serve an additional useful purpose. It has been found that the mag net-ic field produced by heavy high tension current flowing in one phase may exert a strong repelling force upon the adjacent conductors of the other phases. This effect may be so pronounced as to impose a serious lateral strain upon the bus bar and connection supports. The insulating spools not only serve to distribute this lateral strain to the housing but, because of their tendency to roll up the curved inner wall of the pipe, they dissipate the energy of the lateral thrust to a greater or lesser extent. This damping is particularly noticeable when the housing clamber is filled with oil to add a dash pot e ect.

Fig. 4 shows a vertical cross section through a junction box containing a riser connection 52 between a bus bar section 39 running in one direction and a similar bus bar section running at a right angle thereto. The meth 0d of making such connections is well known in the art but this figure serves to show how the connection is enclosed within a housing junction box. The particular arrangement shown is such as might well be employed for the junction boxes 17.

Fig. 7 shows a vertical section through a junction box such as box 9 of- Figs. 1 and 2, wherein two sections of bus bar in the same plane are connected at right angles and a current transformer 53 is located to supply taps for indicating and recording instruments or other devices. Such a junction box, possibly a little larger than an ordinary connection box because of the additional contents, 1s composed of an angle framework and side )lates of the same general type as the smaller oxes. The top plate may be provided with a small hole for the passage of tap 10.

When pipe section runs are so long that some provision must be made for expansion and contraction suitable expansion units may be provided. Such units 8 are indicated in Figs. 1 and 2 and one suitable form is illustrated in section in Fig. 11. This unit is formed from a series of thin annular metal discs 54 which are sealed together alternately along their inner and outer edges. The end discs 55 are secured to flanges 56 whereby the unit may be bolted in position. The action of such a unit or joint is like that of an accordion, contracting and extending under the thrust and pull of the pipe sections connected thereto. The discs may be sealed together and to their end flanges by welding.

Fig. 12 shows a fluid seal arrangement such as may be used to divide the housing chamher into separate sections, forexample between junction boxes 12 and 13 as previously mentioned. Lying between and extending into each junction box is bushing 57 of porcelain or other suitable insulating material through which a short bus bar section 58 extends axially. The ends of the bushing may be covered by small metal caps 59 cemented thereto and providing projecting connectors for attachment to the ends of adjacent bus bar sections. A centrally apertured division plate 60 lies between the adjacent sides of the junction box angle pieces 43 and, with sealing gaskets on each side thereof, is firmly bolted therebetween. A flange 61 is formed about 'the aperture of division plate 60 to embrace a portion of bushing 57. Whatever small space there may be between flange 61 and bushing 57 is filled with a suitable cement. Thus, although the bus bar is in effect continuous the housing chamber in which it lies may be subdivided into separate sections or oil reservoirs. If oil is used asa fluid dielectric such subdivisions may be of importance in localizing leakage. Also where connection is made to transformers the mingling of the relatively inexpensive oil which will give satisfactory results in the bus bar housings with the special and expensive oils deemed quite essential to proper transformer performance will be prevented.

Fig. 13 shows how the housing of an oil switch may be connected to and made a part of the bus bar housing. The details of the switch and its operating mechanism are not shown but the circuit is made and broken in an oil bath by the engagement and disengagement of a movable contact 62 and a fixed contact 63. The oil compartment of the switch casing is provided with a pipe connect in'g flange 6 1 towhich a section of bus bar armoring pipe may be bolted. Thus the oil in the bus bar housing and in the oil switch housing may be supplied from the same reserve tanks.

The oil reserve tanks heretofore mentioned may be made up of the parts used to form junction boxes if desired, thus reducing the variety of differing elements required for a complete system. To make such a tank all but the bottom of the angle piece framework is closed by solid side plates. The bottom of a tank, when it is to be fittedly directly to a junction box, may comprise one of the flan god side plates. The. small pipes, which feed oil from the tank to the housings of the other two phases, may be attached through small holes drilled and tapped in opposite-side side plates.

The foregoing arrangement of armer-insulation for a typical bus and switch station lay-out will serve to illustrate the principles with sufiicient particularity to enable those skilled in the art to provide such re-arrangements and modifications as may be required for any special conditions met in practice. In many situations the arrangement shown and described may be used without any other modifications than merely selecting. the proper numbers and sizes of pipe and junction box units. 1 In the more complicated and special situations which occasionally may arise, the principles taught by the typical embodiment will suffice to show clearly just whatmodifications and re-arrangements will best meet the conditions.

The metallic tubes, which are of considerably greater diameter than the copper conductors and the junction boxes which join the tubes, provide a relatively large superficial heat dissipating surface, and each phase is individually cooled by the surrounding air. The station of my invention is therefore capable of being run at greater current density. with lower consequent temperature rise, than stations of the prior art. The liquid filling between the conductor and the metal sheath i any suitable fluid pump.

. of the other sections.

is a good heat transmitter and conveys and spreads the heat from any localized hot spot, thereby preventing dangerous localized rises in temperature.

It sometimes may be desirable to obtain a greater cooling effect than will be provided if the fluid dielectric is stagnant. When such an effect is desired the fluid dielectric may be caused to circulate through any housing chamber section or sections by employing The complete 3-phase station may be viewed as consisting of three complete single phase sections each having the power supply connection from the transformer, the power supply switch or oil circuit breaker, the bus conductor, and the outgoing line conductor and, if required, the reactor in the line conductor. Each section is completely housed in a grounded tubular metal casing filled with insulating oil, and each section is mechanically and electrically independent The sections are interlaced in order to bring the switches of each section into juxtaposition for convenient joint or 3-phase operation. These independent sections are cross connected by connections which include the potential transformers, and the cross connections including the instrument transformers are housed in oil filled metal casings which are grounded and joined to the casings of the sections.

Having thus illustrated the nature and an embodiment of my invention, what ll claim and desire to secure by United States Letters Patent is as follows:

1. lln an alternating current electrical system having insulated bus bars and connections for each phase, the combination of a series of pipes and junction boxes connected together separately to enclose the bus bars and connections of each phase, said pipes and junction boxes including metal of relatively low magnetic permeability, and a fluid dielectric filling the pipes and junction boxes associated with each phase.

2. An electric high tension alternating current switching station comprising a bus, a connected power line, and oil circuit breakers in said connected line, the bus and the line comprising conductors of multi-phase in permanent proximity to each other, said conductors being all individually and continuously sheathed in fluid tight substantially non-magnetic sheaths which are filled with insulating oil the said power carrying phase conductors and the sheathing thereof throughout the station being so organized and supported as substantially to prevent a fault on one phase from being communicated mechanically or electrically to other phases.

3. An electric high tension alternating current switching station comprising a transformer, a bus connected to the transformer, lines connected to the bus, circuitbreakers in the lines, the bus and line comprising conductors of multiphase in proximity to each other, said conductors being each individually and continuously sheathed from the transformer to the oil circuit breakers and from the circuit breakers to the line terminals of the station, said sheaths each comprising substantially non-magnetic metallic tubes and junction boxes joined together and filled with. insulating oil the said power carrying phase conductors and the sheathing thereof throughout the station being so organized and supported as substantially to prevent a fault on one phase from being communicated mechanically or electrically to other phases.

4-. A. high tension alternating current bus and switch station comprising a main bus and line busses branching therefrom, said busses providing a connection between a source of power and separate distributing lines, said main bus and said line busses comprising individual conductors of different phase associated in close proximity in a permanent structure, and separate continuous grounded substantially non-magnetic metallic sheaths for the individual bus conductors extending throughout the station, said sheaths beingfilled with insulating oil to provide a self-healing insulation of a high order between each phase conductor and ground the said power carrying phase conductors and the sheathing thereof throughout the station being so organized and supported as substantially to prevent a fault on one phase from being communicated mechanically or electrically to other phases.

switch station, a bus comprising bus conductors of large current carrying capacity and relatively short length, each bus conductor comprising a series of conductor sections of relatively short length joined end to end, junction boxes loosely embracing said joints, said junction boxes having joining flanges, thin relatively rigid tubes loosely embracing said conductors, said tubes being provided at their ends with companion flanges secured to the flanges on the junction boxes and forming therewith a rigid continuous fluid tight sheath for each bus conductor, insulating means for supporting said bus conductors substantially centrally in said tubes, and a body of insulating oil filling the connected tubes and unction boxes.

6. In a high tension alternating current bus and switching station, the combination of a bus comprising bus conductors of large current carrying capacity and relatively short length, each bus conductor comprising a series of conductor sections joined end to end, junction boxes loosely embracing said joints, thin relatively rigid tubes of substantially non-magnetic material joined at their ends to the junction boxes and connecting them to form a rigid fluid tight sheath for each bus conductor, a body of insulating liquid filling each sheath, a line comprising line conductors, each line conductor comprisin a plurality of conductor sections joined end to end, said line conductors extending into certain of the junction boxes and being connected to the said'bus conductors at joints therein, line unction boxes loosely embracing the joints in the line conductors, and thin relatively rigid tubes of substantially nonmagnetic material joining said line junction boxes and the corresponding junction boxes of the bus conductors to form individual rigid fluid tight sheaths for the line conductors, and a filling of insulating liquid for each of said line sheaths.

7. In a high tension alternating current bus and switching station of the class described, the combination of a high tension bus consisting of parallel bus conductors of large current carrying capacity, a line comprising parallel line conductors joined to said bus conductors, oil circuit breakers having terminals connected in series in said line conductors between conductor sections and controlling the flow of current from the bus out over the line, said bus conductors and said line conductors comprising conductor sections of relatively short length joined together, junction boxes loosely embracing the joints of said conductor sections and the joints of said conductor sections with the oil circuit breaker terminals, and thin relatively rigid tubes of substantially non-magnetic material loosely embracing the conductor sections and joining the junction boxes, and

forming therewith rigid continuous fluid tight sheaths individual to the enclosed conductors, said sheaths being filled with insulating liquid. I

8. In a high tension alternating'current bus and switch station, the combination of a high .tension bus comprising parallel bus phase conductors of large current carrying capacity and connected lines, each comprising parallel line phase conductors, line circuit breakers connected in the line, said bus conductors and said line conductors comprising short conductor sections joined together and joined to the terminals of the circuit breakers, junction boxes loosely embracing said joints, relatively stiff tubes of substantially non-magnetic material joining said junction boxes to form rigid fluid tight individual sheaths for the conductors of each phase, and liquid insulation filling said sheaths, said sheaths comprising fluid tight barriers for sectionalizing the oil filling of the sheath of each phase.

9. A three-phase alternating current bus and switch station comprising transformers, a bus comprising bus phase conductors, circuit breakers, and a line comprising line phase conductors all connected together in series, enclosing housings for said transformers, enclosing housings for said circuit breakers,

and individual enclosing housings for the separate phase conductors of the bus and of the line, said housings being filled with, insulating liquid and all housings connected to ground the said power carrying phase conductors and the housings thereof throughout the station being so organized as subs-tantially to prevent a fault on one phase from being communicated mechanically or electrically to other phases.

10. A bus and switching station comprising a longitudinally extending bus comprising three parallel bus conductors, lines connected to and extending transversely of said bus conductors, said lines each comprising three parallel line conductors, circuit breakers in series in each of said line conductors, an individual oil filled sheath for each bus conductor completely enclosing and insulating the same, and an individual oil filled sheath for each line conductor completely enclosing and insulating the same the said power carrying phase conductors and the sheathing thereof throughout the station being so organized as substantially to prevent a fault on one phase from being communicated mechanically or electrically to the other phases.

11. In a high tension alternating current bus and switching station,the combination of a three phase bus comprising phase conductors of large current carrying capacity, a three phase line connected thereto comprising phase conductors connected to said bus, circuit breakers controlling the connection of the line phase conductors to the bus phase conductors, said circuit breakers being contained in fluid tight housings, the bus phase conductors and the line phase conductors being completely insulated from each other and from ground by a relatively thin insulating oil, individual containers for the insulating oil for each phase conductor comprising relatively short lengths of thin non-magnetic tubing, junction boxes between adjacent lengths of tubing, said junction boxes and said tubing being joined by flanged couplings, the conductors comprising relatively short lengths joined within the junction boxes, and insulating spacers for centering the conductors in said tubing.

12. As a new article of manufacture, a bus and switching station for high tension alternating current, comprising busses, lines, protective and switching equipment all connected in a compact permanent network and having all power conductors thereof individually sheathed and insulated throughout their length by grounded metallic sheaths containing liquid insulation, the said power carrying phase conductors and the sheathing thereof throughout the station being so organized as substantially to prevent a fault on one phase from being communicated mechanically or electrically to other phases.

13. As a new article of manufacture, a bus and switching station for high tension multi-phase alternating current comprising main busses, line busses, switches for "connecting and disconnecting said main busses and line busses at will, reactors connected individually in series with the line busses,

the said switches and reactors being completely enclosed in grounded metallic casings, and the busses, switches and reactors being interconnected in a compact permanent network having the power conveying conductors thereof individually sheathed and insulated by grounded metallic tubes containing the power conductors and filled with insulating liquid the said power carrying phase conductors and the sheathing thereof throughout the station being so organized as substantially to prevent a fault on one phase from being communicated mechanically or electrically to other phases.

14. As a new article of manufacture, a bus an (1 switching station for high tension multiphase alternating current comprising a main bus consisting of a plurality of parallel main bus conductors, a line bus comprising a plurality of parallel line bus conductors, oil circuit breakers for connecting and disconnecting at will the main bus conductors and line bus conductors, reactors connected individually in series with the line bus conductors, individual oil filled grounded metallic sheaths for each of said conductors and casings for said oil circuit breakers and said reactors, all closely and permanently associated. in a compact network free of any exposed live parts, the said power carrying phase conductors and the sheathing thereof throughout the station being so organized as substantially to prevent a fault on one phase from being communicated mechanically or electrically to other phases.

15. A multi-phase alternating current bus and switch station comprising a compact, permanent network of single phase power conductors and apparatus, all live power conducting parts being continuously sheathed in a grounded fluid tight metal sheath.

16. A multi-phase alternating current bus and switch station comprising a compact, permanent network of single phase power conductors and protecting and switching ap paratus, all live power conducting parts within the station being continuously sheathed in a grounded fluid-tight metal sheath filled with liquid insulation.

17. A bus and switch station comprising the combination of a transformer, a bus, outgoing lines, switches between the bus and outgoing lines, a switch between the transformer and the bus, and conductors joining said parts, saidconductors and said bus throughout the entire extent of the station being sheathed in individual grounded metallic conduits filled with insulating oil.

18. A bus and switch station for 3-phase alternating current power comprising the combination of a bus consisting of phase conductors, an incoming power.v line comprising phase conductors and an outgoing power line comprising phase conductors, switches in said lines controlling the connection of said bus phase conductors with the line phase conductors, all of said phase conductors being sheathed in grounded metallic conduits filled with insulating oil.

19. A bus and switch station for 3-phase alternating current power consisting of a compact permanent network of conductors and switches in which every power conductor is fully sheathed within the confines of the station in individual grounded metallic conduits filled with insulating liquid.

20. A bus and switch station for 3-phase alternating current power comprising a 3- phase bus having connected power supply and take-oflt' lines, and metallic grounded sheaths individual to each phase housing the entire bus and the connections of said lines thereto, said sheaths being filled with insulating oil.

21. A bus and switch station for 3-phase alternating current power comprising a compact network of power conducting conductors and apparatus consisting of the combina-- tion of a 3-phase bus, aconnected power supply line, a connected power take-off line, protective reactors for said take-off lines, and switches between said reactors and the bus, the entire system of power conductors in said network being housed in individual grounded metallic sheaths filled with insulating oil. j

22. In an electric distribution system, a bus and switch station for 3-phase alternating current power comprising a transformer tors, current transformers and potential transformers for said line phase leads, protective reactors connected in said line phase leads, individual grounded metallic sheathing for the conducting parts of each phase, said sheathing extending from the transformer bank to the reactors and individually housing all the power carrying conductors for each phase.

23. In an electric distribution system, a bus and switch station for 3-phase alternating current power comprising a transformer bank having transformer terminal leads, a 3-phase bus, comprising bus phase conductors, phase conductors from the transformer leads to the bus phase conductors, oil circuit breakers in said conductors, current transformers and potential transformers for said transformer leads, a line comprising phase conductors connected to. the said bus phase conductors, current transformers and potential transformers for said line phase leads, protective reactors connected in said line phase leads, individual grounded metallic sheathing for the conducting parts of each phase, said sheathing extending from the transformer bank to the reactors and individually housing all the power carrying conductors for each phase, said sheathing consisting of rel atively short lengths of tubing connected through junction boxes, said junction boxes having removable sides permitting the making of joints in the conductors therewithin, said sheathing being filled with insulating liquid throughout, said current transformers and potential transformers being housed in oil filled junction boxes. v

24. In an electric distribution system, a bus and switch station for 3-phase alternating current power comprising a transformer banlf I having transformer terminal leads, a 3-phase bus comprising bus phase conductors, phase conductors from the transformer leads to the bus phase conductors, oil circuit breakers in said conductors, current transformers and potential transformers for said transformer leads, a line comprising phase conductors connected to the saidbus phase conductors, current transformers and potential transformers for said line'phase leads, protective reactors connected in said line phase lead,'individual grounded metallic sheathing for the gonductactors and individually housing all the power carrying conductors for each phase, said sheathing consisting of relatively short lengths of tubing connected through junction boxes, said junction boxes having removable sides permitting the making of joints in the conductors therewithin, said sheathing being filled with insulating liquid throughout, said current transformers and potential transformers being housed in oil filled junction boxes, the phase conductors comprising relatively short lengths of conductors joined together in the junction boxes, said junction boxes being adapted for making a straight run of sheathed conductor or for making a turn of sheathed conductor.

25. In an electric distribution system, a bus and switch station for 3-phase alternating current power comprising a transformer bank having transformer terminal leads, a

housing all the power carrying conductors for each phase, said sheathin consisting of relatively short lengths of tuliing connected through junction boxes, said junction boxes having removable sides permitting the making of joints in the conductors therewithin, said sheathing being filled with insulating liquid throughout, said current transformers and potential transformers being housed in oil filled junction boxes, the said sheathing having walls sectionalizing the liquid' insulation of a run of conductor, and separate liquid supply means for each section of liquid insulation.

26. In an electric distribution system for 3- phase alternating current power, a bus and switch. station comprising the combination of a 3-phase bus, a 3-phase incoming power supply connection, anoutgoing 3-phase power line, protective and switching means for said bus, the entire bus and its connections being housed in rigid sheaths individual to the phases, saidsheaths being filled with insulating oil and the sheaths and thecontained conductors including expansion joints topermitplay due to thermal expansion and con traction, all arranged in a compact pennanent network. I

27. In an electric distribution system for ply. connection, an outgoing 3-phase power line, protective and switching means for said bus, the entire bus and its connections being housed in rigid sheaths individual to the phases, said sheaths being filled with insulating oil and the sheaths and the contained conductors including expansion joints to permit play due to thermal expansion and contraction, all. arranged in a compact permanent network, said sheaths comprising grounded.

metallic tubes of relatively" short length, and junction boxes for joining lengths of tubing, said tubes and junction boxes providing relatiVely large heat freeing radiators for dissipating the heat generated in the conductors, and said filling of insulating oil serving to transmit heat readily from the contained conductors to the sheatha 28. In a bus and switch station, a longitudinally disposed bus comprising 3-phase conductors disposed in substantially parallel relation, a transverse line comprising 3-phase conductors disposed in substantially parallel relation and off-set from the bus phase conductors, connections from the bus phase conductors to the line phase conductors, disposed substantially at right angles to each connected conductor, junction boxes housing the aforesaid connections and adjacent ends of the conductors, and tubes sheathing said connected conductors and being joined by said junction boxes, said tubes and junction boxes of each phase comprising a liquid-tight casingand a filling of liquid insulation therein.

29. In a bus and switch station, a bus comprising 3 parallel phase conductors disposed longitudinally in substantially a common plane, a transverse line comprising 3 parallel phase conductors disposed transversely in a plane parallel to the first plane, short junction conductors extending at substantially right angles to said planes for joining the bus and line phase conductors, junction boxes housing the aforesaid junction conductors and the adjacent ends of the phase conductors, and tubes sheathing said connected conductors and being joined by said junction boxes, said tubes and junction boxes of each phase comprising a liquid-tight casing, and a filling of liquid insulation therein.

30. A bus and switch station comprising a compact network of incoming and outgoing connections and a bus with suitable protective and switching equipment for the same, the network comprising conductors. and apparatus joined by mechanical joints for providing electrical connection, all of the power conductors within the station being separately sheathed by individual pipes of low magnetic permeability, the joints being housed in j unction boxes of low magnetic permeability, which junction boxes serve to join the pipes for providing communicating sheaths for a given phase, and means for supplying liquid dielectric to the sheaths to keep them filled.

" 31. An electric bus and switch station comprising a power supply connection, a 3-phase bus supplied with current i by said connection, and-outgoing power lines connected to the bus, each phase conductor of the entire bus being sheathed throughout its entire length by individual oil filled grounded metallic sheathing.

32. An electric bus and switch station comprising a power supply connection, a 3-phase bus supplied with current by said connection, and outgoing power lines connected to the bus, and switching and protective equipment for said bus, the bus and all of the connected power carrying conductors including the switching and protective equipment having the separate phases individually housed in grounded metallic sheaths continuous within the station.

33. An electric bus and switch station comprising a power supply connection, a 3-phase bus supplied with current by said connection, outgoing power lines connected to the bus, and switching and protective equipment for said bus, each phase conductor of the entire station'being sheathed throughout its entire length within the station by individual oilfilled grounded metallic sheathing.

34 In a bus and switch station for 3-phase alternating current, the combination of three complete single phase sections, each comprising a power supply conductor, a power supply switch, a bus conductor, and an outgoing conductor, each section being completely housed in a grounded tubular metal casing filled with insulating oil, and each section being mechanically and electrically independent of the others, said sections being interlaced to bring the switches of each section into juxtaposition for convenient 3-phase operation.

35. In a bus and switch station for 3-phase alternating current, the combination of three complete single phase sections, each comprising a power supply conductor, a power supply switch, a bus conductor, and an outgoing vconductor, each section being completely 

